OXYACID EXAMPLES
96
acetic acid
based on ACETATE ion
carbonic acid
based on CARBONATE
ion
nitrous acid
based on NITRITE ion
* The number of hydrogen ions to add to
the polyatomic to make the acid equals
the charge of the polyatomic.
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SUMMING UP CHEMICAL NOMENCLATURE
- You need to be able to tell, by looking at a name OR a formula, what kind of compound
you are working with!
DON'T GET THE NAMING SYSTEMS MIXED UP! EACH KIND OF COMPOUND
IS NAMED WITH ITS OWN SYSTEM!
FROM A CHEMICAL NAME
- If the name has a Roman numeral, the name of a metal, or "ammonium", the compound
is likely IONIC
- If the name has a Greek prefix, the compound is BINARY MOLECULAR
- If the name contains the word "acid":
... and starts with "hydro-", then the compound is a BINARY ACID
... and does not start with "hydro-", the compound is an OXYACID
FROM A CHEMICAL FORMULA
98
- if the formula contains a metal or the
ion, it is likely IONIC
- If the formula starts with H and is not either water or hydrogen peroxide, the compound
is likely an ACID. Which kind?
- BINARY ACIDS contain only two elements
- OXYACIDS contains oxygen
- If the formula contains only nonmetals (and is not an ammonium compound or
an acid), the compound is likely MOLECULAR
Examples:
BINARY MOLECULAR
Name: phosphorus trichloride
OXYACID (hydrogen, phosphate)
Name: phosphoric acid
IONIC (ammonium ion)
Name: ammonium chloride
IONIC (iron - metal!)
Name: iron(III) sulfate
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END OF MATERIAL FOR TEST #2
100
CHEMICAL EQUATIONS
- are the "recipes" in chemistry
- show the substances going into a reaction, substances coming out of the reaction,
and give other information about the process
"yields"
REACTANTS - materials that are needed for
a reaction
PRODUCTS - materials that are
formed in a reaction
COEFFICIENTS - give the ratio of molecules/atoms of one substance to the others
PHASE LABELS - give the physical state of a substance:
(s) -solid
(l) - liquid
(g) - gas
(aq) - aqueous. In other words, dissolved in water
101
CHEMICAL EQUATIONS
REACTION CONDITIONS - give conditions necessary for chemical reaction to
occur. May be:
-
apply heat
- catalysts - substances that will help reaction proceed faster
- other conditions, such as required temperatures
- Reaction conditions are usually written above the arrow, but may also be written
below if the reaction requires several steps or several different conditions
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COEFFICIENTS
- Experimentally, we can usually determine the reactants and products of a reaction
- We can determine the proper ratios of reactants and products WITHOUT further
experiments, using a process called BALANCING
- BALANCING a chemical equation is making sure the same number of atoms of each
element go into a reaction as come out of it.
- A properly balanced chemical equation has the smallest whole number ratio of reactants
and products.
- There are several ways to do this, but we will use a modified trial-and-error
procedure.
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BALANCING
Pick an element. Avoid (if possible) elements that appear in more than one
substance on each side of the equation.
Change the coefficients on substances containing this element so that the
same number of atoms of the element are present on each side. CHANGE
AS LITTLE AS POSSIBLE!
Repeat 1-2 until all elements are done.
Go back and quickly VERIFY that you have the same number of atoms
of each element on each side, If you used any fractional coefficients,
multiply each coefficient by the DENOMINATOR of your fraction.
Use SMALLEST WHOLE NUMBER RATIOS!